Dimensional Photonic Band Gap Characteristics Of The Study

Based on the previous studies of photonic crystal band gap, this paper systematically investigates the bandgap properties and variation of 2-D photonic crystal via plane wave expansion method by introducing the anisotropic material, changing the structure of dielectric cylinder and reducing the symmetry of the photonic crystal structure, etc.The research of band gap generated by photonic crystal which has different lattice structures and different types of materials shows that:Due to the square lattice of isotropic dielectric cylinders in air can not bring about the absolute band gap and the triangular lattice of dielectric cylinders can produce small absolute band gap. When the anisotropic material is used to instead the isotropic material the big absolute band gap is produced because of the dielectric constants of the anisotropic material are different in some directions.Plane wave expansion method is used to calculate the square lattice of anisotropic dielectric cylinders and the triangular lattice of anisotropic dielectric cylinders, respectively. The absolute band gap for square lattice has a width of△ω= 0.03095ωe. For the triangular lattice△ω= 0.03831ωe which is 2.6 times wider than the absolute band gap produced by the isotropic dielectric cylinders.Plane wave expansion method is used to calculate the band gap of TM when the dielectric cylinders are rotated. The internal structures of anisotropic are air and GaAs respectively when the dielectric cylinders are rotated. The affection of TM is discussed when the dielectric cylinder are rotated. The result is that not only the crystal rotational symmetry but also the dielectric constant can affect the band gap of TM. When the internal structure is rotated, there are some band gaps in the high-frequency area. When the dielectric constant of the internal structure is increased, there are many wider band gaps in the high-frequency area.